A positive-engaging coupling of the kind described above is provided between a drive part and a driven part in portable handheld tools such as motor-driven chain saws, brushcutters, cutoff machines or the like. The connection between the drive part and the driven part is such that the driven part is fixed to rotate with the drive part. Thus, in a brushcutter, for example, the clutch drum of a clutch driven by a motor is connected to the driven shaft via a positive-engaging coupling with the drive shaft, in turn, driving a cutterhead. This type of known insert connection is especially problematical with respect to brushcutters. An axial offset between the journalled clutch drum and the driven shaft journalled in a protective tube can occur because of an elastic damping element arranged on the drive motor which is mostly an internal combustion engine. This offset can cause considerable problems to occur after the positive-engaging insertion of the driven shaft into the clutch drum especially because of the high rotational speeds of approximately 7,000 rpm. Radial play occurs in the insert connection and leads to deterioration of this connection with the radial play being caused, for example, by alternating loads which are imparted to the cutting tools of the cutterhead. For this reason, the positive-engaging coupling or the components defining the same must be exchanged after a relatively short duration of operation. An exchange of this kind of components causes the tool not only to be taken out of service for a longer period of time but also consumes time and material and is therefore costly. The product image also suffers when, after a relatively short operating time, always the same parts must be renewed.